The objectives of the Pathology Core are to ensure an accurate diagnosis on all Stanford patients with lymphoma and related leukemias; to handle fresh cells and tissues from these patients as well as from others referred to Stanford for special diagnostic and research studies; to maintain and expand the cell, tissue, and DNA banks for current and future research needs; and to distribute and refile cells and tissues for individual project investigators. An immunophenotypic profile which includes lineage, growth fraction, apoptosis index, P-glycoprotein, bcl-2, p53 and T-cell infiltrate will be generated. Standard flow cytometric and tissue phenotyping methods will be utilized. In addition, all Ig positive cases will be stained for VH 4.21 with antibody 9G4. The new antibodies which are generated will be screened on relevant normal and neoplastic cells and tissues prior to their usage in research studies. For the high risk patients PCR with probes for t(14;18) will identify the subset of patients with this translocation and be used to monitor tumor cell contamination in peripheral blood stem cells either unmanipulated, after density centrifugation, or following the purging procedure. Fore the remaining high risk patients a probe specific for the rearranged immunoglobulin heavy chain VDJ sequences will be constructed. CDR3PCR will be performed using consensus VH and JH primers, the product cloned and sequenced, and a specific oligonucleotide probe designed. In addition, lymphomas from the high risk patients will be studied for bcl-6 rearrangements.